9D-USTE Spacetime Curvature Modulation: A Purely Geometric Mechanism for Anti-Gravity Propulsion without Exotic Matter

We propose a novel framework for anti-gravity propulsion derived from the dimensional reduction of a 9-dimensional Ultra-Spacetime-Time-Energy (9D-USTE) manifold. The fundamental spacetime structure is strictly defined as a product of a 3-dimensional macroscopic space and a compact 6-dimensional internal manifold (9D = 3 + 6), where time is treated as a dynamic evolution parameter rather than an additional spatial dimension. Unlike traditional Alcubierre-type metrics that rely on exotic matter violating energy conditions, our model achieves localized curvature modulation via the topological sign inversion of the 6D internal scalar curvature R₆. We demonstrate that a geometric phase transition in the internal manifold induces a controllable effective cosmological constant ₄₅₅ in 3D space, enabling repulsive gravitational effects. This purely geometric mechanism preserves causality, satisfies all energy conditions at the fundamental 9D level, and naturally reduces to classical gravity in the low-energy limit, providing a consistent and physically viable foundation for gravitational engineering and advanced propulsion.